The goal of this study is to clarify the extent to which postmenopausal estrogen deficiency places women at increased risk for tooth loss -- an oral health outcome of clear functional significance. Specifically, this investigation will: 1) establish the relative risk of tooth loss in postmenopausal women who have not received estrogen replacement therapy; 2) more reliably quantify and characterize tooth loss attributable to postmenopausal estrogen deficiency; and 3) describe the relationship between estrogen replacement therapy and prevention of tooth loss in terms of overall use, duration of therapy, and effects after discontinuation. This project will employ a group difference approach using a retrospective quasi-experimental research design. Two groups of 125 women who are similar in other respects but who differ in their exposure to postmenopausal estrogen replacement therapy (ERT) will be compared to assess the number and pattern of teeth lost between pre- and postmenopause using dental records that are continuous through menopause. The independent variable will be exposure to ERT, and the dependent variable will be the number of teeth lost between pre- and postmenopause. Subjects are women who are at least five years postmenopause with continuous dental records dating back just prior to menopause. Women with selected characteristics known to influence bone health, estrogen levels, or tooth loss will be excluded from the study, as will those with inadequate dental records. A pilot-tested self-report survey will be used to gather background demographic and medical information on each subject. This information will be validated through dental chart review, along with information from physician and pharmacy records. Pre- and postmenopause information on the numbers and locations of teeth lost will be abstracted from tooth charting, radiographs, and progress notes contained in the dental record. For analysis, subjects will be segregated into an estrogen-exposed group and a non-exposed group -- and matched by chronological age, menopausal age, and socioeconomic status. With postmenopausal tooth loss measured quantitatively, two-tailed T-tests will be used to assess statistical differences in mean tooth loss between the two groups of subjects with similar characteristics (i.e. menopausal age, income, education), but who vary in their exposure to exogenous estrogen. Maxillary vs. mandibular tooth loss will also be compared in a similar manner, and the correlations determined between tooth loss and duration of ERT, point of ERT initiation, and point of ERT discontinuation.